In a snowy region of Izabe Island, Ash and his friends take a rest at a Pokémon Center. As they're greeted by Nurse Joy, a Snorunt steals Ash's badges right out of his backpack! Nurse Joy explains that this mischievous Snorunt is just having fun, but Ash certainly isn't. He sends Corphish and Pikachu to get his badges back, and the chase is on!
The chase leads to the kitchen, where Team Rocket is busy helping themselves to all the food. Snorunt sends the thieves packing before leaping out the window, hotly pursued by Ash. As Snorunt taunts Ash, it slips and falls down an icy slope. Ash manages to save it, but he's knocked out in the process and his friends are unable to find him before a blizzard forces them back indoors.
Ash awakens in a snug snow shelter built by Snorunt. It swipes his hat and takes it to the Pokémon Center, alerting Ash's friends. They follow Snorunt back to the shelter on snowmobiles but just as they reach Ash, Team Rocket grabs Snorunt and Pikachu! Snorunt breaks free, then helps Ash stop Team Rocket and save his friend.
It seems Snorunt stole Ash's badges because it wanted to play with him. Ash invites Snorunt to join him, but first he must prove he's capable of capturing this wily Pokémon. With Pikachu's help, he does capture Snorunt—although it looks like this Pokémon may still be a real handful!
While on their way to Cerosi Town, Ash and his friends arrive at a Pokémon Center shortly before a blizzard is expected to hit. As Brock tries to chat up Nurse Joy, a Snorunt comes in and cools Brock down with an Icy Wind. Joy introduces the group to Snorunt, admitting that it's a bit of a trickster. Snorunt rummages through Ash’s backpack and walks off with Ash's Badge case in hand. Joy tells Ash not to worry, that it always returns things before long. Ash is not inclined to wait, and has Pikachu and Corphish chase Snorunt down. When they have it cornered, Ash demands that it return his Badges. It returns the Stone Badge and uses Double Team to get away with the rest.
Ash, his friends and Joy begin searching the Pokémon Center for Snorunt, when they find the Knuckle Badge lying on the floor. Ash doesn't like the idea that it's returning his Badges one at a time. Suddenly, Corphish charges off into the kitchen, and the others follow, suspecting that it has sensed Snorunt. Ash orders Snorunt to appear, but Team Rocket emerge from behind some boxes, food in hand and mouth. They deny any involvement with his Badges, and say they weren't even doing anything wrong aside from taking food without permission. Snorunt makes an appearance, with Ash and his Pokémon chasing after it. The Rocket trio don't like being ignored and start shouting to get attention. They succeed, and when Joy yells at them for stealing the Center's food, Snorunt suddenly becomes very serious and attacks them. Working together, Corphish and Snorunt defeat Team Rocket, Corphish sends them flying with Crabhammer, and Snorunt opens a window to let them out. Ash thanks Snorunt for its help, and Snorunt replies by handing over the Badge case. Snorunt plays a final trick on Ash, freezing him with an Icy Wind before bounding outside with the Badge case still in hand. Ash recklessly leaps through the open window to give chase just as the blizzard looks ready to start. Brock and the others realize the situation is dire, though they rush outside to retrieve Ash.
Ash catches up with Snorunt at the edge of a steep hill, where it dances around a bit to taunt him. The ice at the edge crumbles under its foot, and it ends up sliding out of control down a hill. Ash grabs Snorunt and joins the trip down, assuring it they’ll be fine. When they're about to slide into a large rock, Ash maneuvers them so that he takes the full impact on his back, protecting Snorunt. Ash is knocked out, and Snorunt is unable to wake him as the blizzard whips up. Brock and others retreat back to the Pokémon Center without Ash. Ash soon wakes up to find himself in a snow cave with Snorunt. He thanks it for saving him, and it offers him an apple. Ash initially refuses to avoid more of Snorunt’s trickery, but it assures him otherwise, so the pair share a bite of the apple each. Snorunt gives him a couple more apples before taking his hat and walking off into the storm. At the Pokémon Center, it delivers the hat to the others. As soon as the storm is over, they ask it to lead them to Ash, and set off on snowmobiles. They find Ash right where Snorunt left him, and there is a reunion.
As Ash once again asks Snorunt to give his Badges back, Team Rocket comes out of nowhere and captures both Snorunt and Pikachu, putting them in boxes. However, Snorunt breaks out of its box with Icy Wind. It uses another Icy Wind against Team Rocket, but Wobbuffet uses Mirror Coat to send the attack back. Team Rocket manages to escape in their Meowth balloon.with Pikachu. Though Ash, his friends, and Joy follow them on the snowmobiles. Team Rocket manages to speed up, but Joy leads everyone to a shortcut through the forest. With the added air from a jump, Ash tosses Snorunt directly at Team Rocket’s balloon. Snorunt lands inside the basket and promptly freezes the trio and the balloon with a blast of its Icy Wind. It then jumps out with the still captive Pikachu before the balloon crashes down. Ash soon gets Pikachu out of the box. Team Rocket pops out of the snow. Jessie calls out Seviper while James calls out Cacnea. They go in for Bite and Needle Arm, but are frozen solid by Snorunt’s Icy Wind. Pikachu uses Thunderbolt to knock them back into Team Rocket and sends them blasting off again.
Snorunt is still reluctant to return the Badges. Ash admits that he really needs to go, though Snorunt begins tugging on his coat in a bid to get him to stay longer. Nurse Joy quickly realizes that Snorunt actually likes Ash, and kept the Badges so they could play together longer. Ash tries to solve the dilemma by inviting Snorunt to come with him. Snorunt gestures that it wants to battle and Ash takes up the challenge. Ash calls on Pikachu to use Iron Tail, though Snorunt uses Double Team to disorientate its opponent before striking Pikachu with a Headbutt. Snorunt continues to encircle Pikachu with its Double Team. To overcome this tactic, Ash has Pikachu aim an Iron Tail on the ground which causes snow to fly everywhere and gets rid of the copies. Pikachu finishes Snorunt off with a Quick Attack followed by a Thunder. The Badge case is incidentally dropped as Snorunt hits the ground. Ash sees his chance and throws a Poké Ball, which successfully catches Snorunt. Afterward, Nurse Joy heals Snorunt up before it is introduced to all the group's Pokémon. Corphish gets a little too close for comfort, so Snorunt freezes it with an Icy Wind. May has Combusken thaw Corphish with a Fire Spin, and Ash sits down for a little talk with Snorunt about acceptable behavior.